The present invention relates to paper handling apparatus, in particular to a portable sawing apparatus, and more specifically to sawing apparatus that is mountable upon a reel, for example a reel of paper.
When the large industrial paper reels are produced either in the wrong size or subsequently become redundant, or when ends of the reels are damaged they need to be re-sized before being accepted by the printing industry. There are generally two methods of such treatment currently carried out in the paper industry. These take the form of xe2x80x9crewindingxe2x80x9d and xe2x80x9csawingxe2x80x9d. Paper reels are generally cylindrical in shape and the areas that often may require treatment are the planar end faces of the reel.
The most conventional treatment process involves rewinding. As its name suggests, the process involves the rewinding of the parent paper reel, through a mechanism of rider rolls and drive drums to form a new xe2x80x9crewoundxe2x80x9d reel of paper. With this process the reel diameter is able to be changed and also there is the ability to slit multiple reels. There are, however, several disadvantages to the rewinding process. A high level of infrastructure is required, and as a result, the equipment is very expensive and requires skilled operators to operate the machinery at the required efficiency. Rewinding also has been shown to change the original mill tension and therefore can place excessive tensile pressure on the reel which can lead to fracturing of the fibre in the paper, or web breaks during printing.
Furthermore, due to the size and complexity of the equipment required, the rewinding process must be carried out at a fixed location, wherein the paper reels must be brought to the rewinding site in order to be treated under the process. The width of the paper reels can vary from 0.5 m to 3 m with an outer diameter of up to 1.8 m. Amongst other disadvantages, this vastly increases the costs involved with the process with large transportation and storage costs being a major contributing factor. Also, throughout the industry, a stigma is attached to rewound reels, as the receiver of such reels knows that they are not in the original condition that they were in prior to undergoing the rewinding process.
A more recent method of paper reel treatment involves sawing of the paper reels to take off damaged material. Unlike rewinding, the process of sawing does not have a stigma attached to it within the industry, mainly because the original mill tension is not affected during the process.
In the majority of current sawing methods, the paper reel itself is laid on its side as it passes through the sawing machinery. The speed of operation is greatly increased while the ability to slit multiple reels is also maintained. Furthermore, only semi-skilled operators are needed to operate the required machinery.
The machinery itself however has several disadvantages, being similar to that for rewinding, in that a high level of infrastructure is required, resulting in high cost and fixed location. Reel diameters cannot be changed and any out-of-shape reels cannot be sawn, through the process. Furthermore, the quality of the sawn reels, using this horizontal sawing process, is generally not good enough to be accepted by the printing industry directly. The process must therefore be followed by a rewinding process in order to bring the reels up to the correct standard for acceptance.
Another method of paper reel sawing involves the paper reel being placed in an upright position within the apparatus. This method provides greater mobility and also produces sawn reels of the required quality for acceptance by the printers. The vertical sawing apparatus is mobile, but its size is such that large specialised vehicles are needed in order to transport it from one site to another. The size also means that a substantial amount of time, in excess of two hours, is required to set up the apparatus for use, and to dismantle the apparatus fo transportation. As a result, the use of the vertical sawing method is only available to customers who have a high level of infrastructure to accommodate the method and its related apparatus. Furthermore, the efficiency of the method is dependent on the co-operation of third party truck drivers used for the transportation of the machinery.
An aim of the present invention is to provide sawing apparatus that overcomes or at least alleviates these problems, by providing apparatus that is easily portable from site to site without the need for specialised transportation requirements.
Accordingly, the present invention provides a portable sawing device comprising
a saw blade mountable on a carriage slide,
a saw drive motor to drive the saw blade,
means for mounting the carriage slide on to an object to be sawn, and
means for moving the carriage slide across the surface of the object to be sawn so as to bring the saw blade into contact with the object to be sawn.
The sawing apparatus is most suitable to cutting sheet material rolled around a cylindrical core. For the purposes of the description, this object to be cut be exemplified by a reel of paper, although it will be appreciated that the invention is also applicable to other material. Industrial paper reels are produced in width sizes ranging from 0.5 m to 3 m with an outer diameter of up to 1.8 m and their weights range from 500 kgs to in excess of 3,000 kg. These dimensions make transportation of the reels to and from the sawing site costly and time consuming. The vertical sawing xe2x80x9cmobilexe2x80x9d apparatus is able to be transported from site to site, however its complex infrastructure, size and weight (around 6,000 kg) is such that transportation to the paper reel storage site, as opposed to the transportation of paper reels to the sawing site, is inefficient. The size and structure of the apparatus of the present invention, however, is such that it weighs considerably less than the fixed or mobile apparatus described above. As a result the apparatus is xe2x80x9cportablexe2x80x9d in that it is more efficient to transport the sawing apparatus to the paper reel site, as opposed to transporting the paper reels to the sawing site. This significantly reduces transportation costs associated with the sawing process.
The saw blade is preferably cylindrical although it can be envisaged that the saw blade is linear and undergoes a reciprocating action.
The object to be sawn preferably takes the form of a sheet material rolled around a cylindrical core, for example a reel of paper.
Preferably the fixing means comprises an air shaft which is inserted into the central core of the reel of paper.
The reel of paper may be fixed and freestanding, requiring no specialist support, or alternatively it may be mounted on a rotatable base, the reel of paper thus rotating when the base is in rotation.
The carriage moving means preferably comprises a motor for rotating the carriage slide over a proximal, planar, end face of the reel of paper, together with a further motor for moving the carriage across the face of the reel of paper.
Opposing taper ball bearings and a cam mechanism enabling alteration of the angle between the carriage slide and the paper reel may be provided within the carriage slide together with a indicator mounted on the carriage slide to indicate when the carriage slide is parallel with the top surface of the paper reel.